linux-kernel - Re: [PATCH 2.6.25.4] hwmon: HP Mobile Data Protection System 3D ACPI driver -- please review!

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Date:	Fri, 06 Jun 2008 17:37:33 +0200
From:	Pau Oliva Fora <pau@...ack.org>
To:	Eric Piel <eric.piel@...mplin-utc.net>
CC:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Andrew Morton <akpm@...l.org>, pavel@....cz,
	Arjan van de Ven <arjan@...radead.org>,
	"Mark M. Hoffman" <mhoffman@...htlink.com>,
	Yan Burman <burman.yan@...il.com>,
	LKML <linux-kernel@...r.kernel.org>,
	HWMON <lm-sensors@...sensors.org>
Subject: Re: [PATCH 2.6.25.4]  hwmon: HP Mobile Data Protection System 3D
 ACPI driver -- please review!

Eric Piel wrote:
>> I would recommend converting the input piece to input_polled_device
>> instead of managing the polling thread by yourselves.
> Yes, you are right, I had forgotten about this one! That said, for now 
> I'm working on removing the polling and relying only the interrupts. So 
> if it works that shouldn't be needed :-)
> 

I think going to interrupt-only approach will cause a problem in the HTC 
Shift:

In CTRL_REG2 (21h) if you set to 1 the Interrupt ENable (IEN) field the 
device shuts down.

I guess HTC took the "polling" approach in the windows driver, and they 
enable the interrupt when the sensor reports a "free fall" event, to 
have the disk parked and protect the hardware from being damaged.

Maybe you can keep the input_polled_device together with interrupts and 
select one or the other depending on DMI information (same as for 
swaping the axis, etc.)

Cheers,

	Pau Oliva
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